diff --git a/addons/mail/static/src/components/channel_preview_view/channel_preview_view.xml b/addons/mail/static/src/components/channel_preview_view/channel_preview_view.xml
index 1c898ca68e7..d3d6eae3e71 100644
--- a/addons/mail/static/src/components/channel_preview_view/channel_preview_view.xml
+++ b/addons/mail/static/src/components/channel_preview_view/channel_preview_view.xml
@@ -46,7 +46,7 @@
                         <span class="flex-grow-1"/>
                         <t t-if="channelPreviewView.thread.lastMessage and channelPreviewView.thread.lastMessage.date">
                             <small class="o_NotificationListItem_date o_ChannelPreviewView_date flex-shrink-0 text-500" t-att-class="{ 'o-muted': channelPreviewView.channel.localMessageUnreadCounter === 0 }">
-                                <t t-esc="channelPreviewView.thread.lastMessage.date.fromNow()"/>
+                                <t t-esc="channelPreviewView.thread.lastMessage.momentDate.fromNow()"/>
                             </small>
                         </t>
                     </div>
diff --git a/addons/mail/static/src/components/thread_needaction_preview/thread_needaction_preview.xml b/addons/mail/static/src/components/thread_needaction_preview/thread_needaction_preview.xml
index 5cfab1dc3ad..db46b9a4c32 100644
--- a/addons/mail/static/src/components/thread_needaction_preview/thread_needaction_preview.xml
+++ b/addons/mail/static/src/components/thread_needaction_preview/thread_needaction_preview.xml
@@ -42,7 +42,7 @@
                         <span class="flex-grow-1"/>
                         <t t-if="threadNeedactionPreviewView.thread.lastNeedactionMessageAsOriginThread and threadNeedactionPreviewView.thread.lastNeedactionMessageAsOriginThread.date">
                             <small class="o_NotificationListItem_date o_ThreadNeedactionPreview_date flex-shrink-0 text-500">
-                                <t t-esc="threadNeedactionPreviewView.thread.lastNeedactionMessageAsOriginThread.date.fromNow()"/>
+                                <t t-esc="threadNeedactionPreviewView.thread.lastNeedactionMessageAsOriginThread.momentDate.fromNow()"/>
                             </small>
                         </t>
                     </div>
diff --git a/addons/mail/static/src/models/message.js b/addons/mail/static/src/models/message.js
index e8fcfed8427..44b4c1f1534 100644
--- a/addons/mail/static/src/models/message.js
+++ b/addons/mail/static/src/models/message.js
@@ -28,7 +28,7 @@ registerModel({
                 data2.body = data.body;
             }
             if ('date' in data && data.date) {
-                data2.date = moment(str_to_datetime(data.date));
+                data2.date = data.date;
             }
             if ('email_from' in data) {
                 data2.email_from = data.email_from;
@@ -345,10 +345,21 @@ registerModel({
                 return !this.messaging.isCurrentUserGuest && !this.isTemporary && !this.isTransient;
             },
         }),
+        date: attr(),
         /**
          * Determines the date of the message as a moment object.
          */
-        date: attr(),
+        momentDate: attr({
+            compute() {
+                if (!this.date) {
+                    return clear();
+                }
+                if (!moment.isMoment(this.date)) {
+                    return moment(str_to_datetime(this.date));
+                }
+                return this.date;
+            }
+        }),
         /**
          * States the date of this message as a string (either a relative period
          * in the near past or an actual date for older dates).
@@ -360,7 +371,7 @@ registerModel({
                     // mainly done to avoid flicker inside the UI.
                     return this.env._t("Today");
                 }
-                const date = this.date.format('YYYY-MM-DD');
+                const date = this.momentDate.format('YYYY-MM-DD');
                 if (date === moment().format('YYYY-MM-DD')) {
                     return this.env._t("Today");
                 } else if (
@@ -370,7 +381,7 @@ registerModel({
                 ) {
                     return this.env._t("Yesterday");
                 }
-                return this.date.format('LL');
+                return this.momentDate.format('LL');
             },
         }),
         /**
@@ -378,10 +389,10 @@ registerModel({
          */
         datetime: attr({
             compute() {
-                if (!this.date) {
+                if (!this.momentDate) {
                     return clear();
                 }
-                return this.date.format(getLangDatetimeFormat());
+                return this.momentDate.format(getLangDatetimeFormat());
             },
         }),
         email_from: attr(),
@@ -705,10 +716,10 @@ registerModel({
         recipients: many('Partner'),
         shortTime: attr({
             compute() {
-                if (!this.date) {
+                if (!this.momentDate) {
                     return clear();
                 }
-                return this.date.format('hh:mm');
+                return this.momentDate.format('hh:mm');
             },
         }),
         subject: attr(),
diff --git a/addons/mail/static/src/models/message_view.js b/addons/mail/static/src/models/message_view.js
index 48ff202bd98..736c5c4d613 100644
--- a/addons/mail/static/src/models/message_view.js
+++ b/addons/mail/static/src/models/message_view.js
@@ -380,10 +380,10 @@ registerModel({
                     return clear();
                 }
                 const now = moment(this.clockWatcher.clock.date.getTime());
-                if (now.diff(this.message.date, 'seconds') < 45) {
+                if (now.diff(this.message.momentDate, 'seconds') < 45) {
                     return this.env._t("now");
                 }
-                return this.message.date.fromNow();
+                return this.message.momentDate.fromNow();
             },
         }),
         /**
diff --git a/addons/mail/static/src/models/notification_group.js b/addons/mail/static/src/models/notification_group.js
index fb189b86c6a..fe936f1de38 100644
--- a/addons/mail/static/src/models/notification_group.js
+++ b/addons/mail/static/src/models/notification_group.js
@@ -72,8 +72,8 @@ registerModel({
              */
             compute() {
                 const dates = this.notifications
-                    .filter(notification => notification.message && notification.message.date)
-                    .map(notification => notification.message.date);
+                    .filter(notification => notification.message && notification.message.momentDate)
+                    .map(notification => notification.message.momentDate);
                 if (dates.length === 0) {
                     return clear();
                 }
diff --git a/addons/mail/static/src/models/thread_view.js b/addons/mail/static/src/models/thread_view.js
index 4ca001f0257..ad623a5ed40 100644
--- a/addons/mail/static/src/models/thread_view.js
+++ b/addons/mail/static/src/models/thread_view.js
@@ -169,7 +169,7 @@ registerModel({
             if (!prevMessage.date && message.date) {
                 return false;
             }
-            if (message.date && prevMessage.date && Math.abs(message.date.diff(prevMessage.date)) > 60000) {
+            if (message.momentDate && prevMessage.momentDate && Math.abs(message.momentDate.diff(prevMessage.momentDate)) > 60000) {
                 // more than 1 min. elasped
                 return false;
             }